Paper feeding apparatus and image forming apparatus

ABSTRACT

A paper feeding apparatus includes a rack that stores sheets in a vertically placed state, a first conveying roller that conveys a sheet extracted from the rack in a first direction in an erected state, a scraper that scrapes a surface of the sheet conveyed in the erected state by the first conveying roller, and a second conveying roller that conveys the sheet, the surface of which is scraped by the scraper, in a second direction different from the first direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 61/112,636, filed Nov. 7, 2008.

TECHNICAL FIELD

The present invention relates to, for example, a paper feeding apparatus that feeds a sheet as a recording medium, on which an image is formed, to an image forming apparatus such as a copying machine or a printer.

BACKGROUND

In recent years, in order to reduce environmental load or reduce an amount of emission of carbon dioxide, image forming apparatuses such as a printer, a copying machine, and a digital multi function peripheral often reuse sheets. Some image forming apparatus in the past receives sheets to be reused from a paper feeding apparatus. The paper feeding apparatus sequentially feeds sheets set by a user to the image forming apparatus. For example, some image forming apparatus reuses sheets on which images are printed with color-fadable inks or toners. The user sets sheets on which images are printed with color-fadable inks or toners in the paper feeding apparatus. The image forming apparatus erases the images on the sheets received from the paper feeding apparatus and reuses the sheets.

In the paper feeding apparatus in the past, the user visually checks the state of a sheet to be reused. In other words, the user sets, in the paper feeding apparatus, a sheet that the user considers reusable in the user's own judgment. However, the user is likely to set a non-reusable sheet in the paper feeding apparatus. For example, the user is likely to set a sheet in the paper feeding apparatus without noticing that remaining dust (e.g., waste of an eraser) adheres to the surface of the sheet. The user is likely to set a sheet in the paper feeding apparatus without noticing that staples enter the paper feeding apparatus together with the sheet. Foreign matters that enter the paper feeding apparatus together with the sheet cause damage to the paper feeding apparatus or the image forming apparatus. A sheet having wrinkles, curls, or the like is highly likely to induce various deficiencies in the paper feeding apparatus or the image forming apparatus. For example, when the paper feeding apparatus feeds the sheet having wrinkles, curls, or the like to the image forming apparatus, a corner of the sheet is folded, a part of an image printed on the sheet is lost, or the wrinkles in the sheet increase.

SUMMARY

A paper feeding apparatus according to an aspect of the present invention includes: a rack that stores sheets in a vertically placed state; a first conveying roller that conveys a sheet extracted from the rack in a first direction in an erected state; a scraper that scrapes the surface of the sheet conveyed in the erected state by the first conveying roller; and a second conveying roller that conveys the sheet, the surface of which is scraped by the scraper, in a second direction different from the first direction.

An image forming apparatus according to another aspect of the present invention includes: a rack that stores sheets in a vertically placed state; a first conveying roller that conveys a sheet extracted from the rack in a first direction in an erected state; a scraper that scrapes the surface of the sheet conveyed in the erected state by the first conveying roller; a second conveying roller that conveys the sheet, the surface of which is scraped by the scraper, in a second direction different from the first direction; and a printer that forms an image on the sheet conveyed by the second conveying roller.

An image forming method according to still another aspect of the present invention includes: storing sheets in a rack in a vertically placed state; conveying a sheet extracted from the rack in a first direction in an erected state; scraping the surface of the sheet conveyed in the erected state; conveying the sheet, the surface of which is scraped, in a second direction different from the first direction; and forming an image on the sheet conveyed in the second direction.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a diagram of a configuration example of a digital multi function peripheral;

FIG. 2 is a diagram of a configuration example of a collection rack of a paper feeding apparatus;

FIG. 3 is a diagram of a configuration example of the collection rack of the paper feeding apparatus;

FIG. 4 is a diagram of a paper feeding apparatus according to a first configuration example;

FIG. 5 is a diagram of the state of blades until the leading end of a sheet reaches a carry-out roller;

FIG. 6 is a diagram of the state of the blades during conveyance of the sheet by the carry-out roller;

FIG. 7 is a diagram of a paper feeding apparatus according to a second configuration example; FIG. 8 is a diagram of a paper feeding apparatus according to a third configuration example; and

FIG. 9 is a diagram of a paper feeding apparatus according to a fourth configuration example.

DETAILED DESCRIPTION

An embodiment of the present invention is explained in detail below with reference to the accompanying drawings.

First, the configuration of a digital multi function peripheral 1 as an image forming apparatus is explained.

FIG. 1 is a diagram of a configuration example of the digital multi function peripheral 1. The digital multi function peripheral 1 shown in FIG. 1 includes a printer 2, a scanner 3, and a finisher 4. The printer 2 forms an image on a sheet. The scanner 3 converts an image of a document into image data. The finisher 4 processes a sheet subjected to image formation.

The digital multi function peripheral 1 realizes various functions according to cooperation of the printer 2, the scanner 3, and the finisher 4. For example, the digital multi function peripheral 1 has a copy function for printing, with the printer 2, an image read by the scanner 3 on a sheet and a finishing function for processing, with the finisher 4, a sheet on which an image is printed by the printer 2.

In the digital multi function peripheral 1 shown in FIG. 1, the printer 2 includes an accumulating unit 10, an image forming unit 12, and an erasing unit 18. In the digital multi function peripheral 1 shown in FIG. 1, the finisher 4 includes a paper discharge tray 14 and a paper feeding apparatus 16.

The accumulating unit 10 stores sheets on which images are formed. The accumulating unit 10 includes plural sheet cassettes. The sheet cassettes respectively store sheets classified according to sizes, types, or the like. The sheet cassettes store sheets fed by the paper feeding apparatus 16. The sheet cassettes pick up plural sheets stored therein one by one and carry out the sheet. The accumulating unit 10 feeds one sheet picked up from a selected sheet cassette to the image forming unit 12.

The image forming unit 12 forms an image on the sheet fed from the accumulating unit 10. The image forming unit 12 forms an erasable image on the sheet. The image forming unit 12 can be realized by printers of various systems as long as the printers can form images with erasable image forming materials. For example, the image forming unit 12 can be realized by an ink jet printer, a laser printer, or a thermal transfer printer.

In FIG. 1, a configuration example of a color ink jet printer as the image forming unit 12 is shown. In the configuration example shown in FIG. 1, the image forming unit 12 includes a conveying roller pair 21, a registration roller pair 22, a driven roller 23, a driving roller 24, a conveyor belt 25, and an ink jet head group 26 (26Y, 26M, 26C, and 26Bk).

The conveying roller pair 21 conveys a sheet, which is fed from the accumulating unit 10, to the registration roller pair 22. The registration roller pair 22 conveys the sheet onto the conveyor belt 25 at predetermined timing. Tension is applied to the conveyor belt 25 by the driving roller 24 and the driven roller 23. The conveyor belt 25 is driven according to the rotation of the driving roller 24. The conveyor belt 25 conveys the sheet while attracting the sheet to the belt with a roller, a fan, or the like. The conveyor belt 25 conveys the sheet on which an image is formed by the ink jet head group 26 to the paper discharge tray 14.

The ink jet head group 26 includes an ink jet head 26Y, an ink jet head 26M, an ink jet head 26C, and an ink jet head 26Bk. The ink jet heads 26Y, 26M, 26C, and 26Bk are set in order along the conveyor belt 25. The ink jet head 26Y ejects a color-fadable yellow (Y) ink. The ink jet head 26M ejects a color-fadable magenta (M) ink. The ink jet head 26C ejects a color-fadable cyan (C) ink. The ink jet head 26Bk ejects a color-fadable black (Bk) ink. The ink jet heads 26Y, 26M, 26C, and 26Bk respectively form images of the colors on the sheet. The ink jet heads 26Y, 26M, and 26C respectively eject inks corresponding to a yellow component, a magenta component, and a cyan component in a color image. The ink jet head group 26 prints the images of the colors on the sheets one on top of another to thereby form a color image on the sheet.

The image forming unit 12 conveys the sheet on which the image is formed to the paper discharge tray 14 of the finisher 4. The paper discharge tray 14 of the finisher 4 stores the sheet on which the image is formed by the printer 2. A user receives, as a print result, the sheet stored in the paper discharge tray 14.

The finisher 4 includes the paper feeding apparatus (a reuse paper collecting apparatus) 16 besides the paper discharge tray 14. The paper feeding apparatus 16 feeds sheets to be reused to the printer 2. The paper feeding apparatus 16 includes a collection rack 31 and a conveying mechanism 32. The collection rack 31 stores the sheets to be reused. The collection rack 31 stores the sheets in an erected state on the bottom surface of the finisher 4. The conveying mechanism 32 conveys the sheets in the collection rack 31 one by one. The conveying mechanism 32 extracts the sheets in order from one stored in the collection rack 31 earliest. The conveying mechanism 32 conveys the sheet while rectifying the sheet. The conveying mechanism 32 conveys the sheet while removing dust adhering to the sheet. The conveying mechanism 32 feeds the sheet to the printer 2.

The erasing unit 18 of the printer 2 captures the sheet fed by the paper feeding apparatus 16. The erasing unit 18 includes an erasing mechanism 18 a. The erasing mechanism 18 a erases an image formed of an erasable image forming material on the sheet. The erasing mechanism 18 a has a configuration corresponding to characteristics of image forming materials that should be erased. For example, when the erasing mechanism 18 a erases an image formed with an ink to be erased by heating, the erasing mechanism 18 a includes a heating head that heats the sheet.

The erasing unit 18 only has to be an erasing unit that erases the image on the sheet fed from the paper feeding apparatus 16 until the sheet reaches the image forming unit 12. For example, the erasing mechanism 18 a only has to be set in a place along a path through which the sheet reaches the registration roller pair 22 of the image forming unit 12 in the printer 2. As an example, the erasing mechanism 18 a may be set to erase an image on a sheet immediately after the sheet is extracted from the sheet cassette in the accumulating unit 10.

The configuration of the paper feeding apparatus 16 is explained below.

FIGS. 2 and 3 are diagrams of configuration examples of the collection rack 31 of the paper feeding apparatus 16.

In the configuration example shown in FIG. 2, the finisher 4 includes a hatch 41 on the front surface thereof. The hatch 41 is openable and closable on the front side. When the hatch 41 is opened, the collection rack 31 of the paper feeding apparatus 16 appears. The collection rack 31 includes a moving mechanism 42 that moves from the inside of the finisher 4 to the front side. The user can set sheets to be reused in the collection rack 31 in a state in which the collection rack 31 is drawn out from the inside of the finisher 4 to the front side.

In the configuration shown in FIG. 2, the user sets reuse sheets in a procedure explained below.

The user opens the hatch 41. In a state in which the hatch 41 is opened, the user draws out the collection rack 31 from the inside of the finisher 4 to the front side. The user sets, in an erected state, sheets to be reused in the collection rack 31 drawn out to the front side. The user pushes the collection rack 31, in which the reuse sheets are set, into the finisher 4. The user closes the hatch 41.

In the configuration example shown in FIG. 3, the finisher 4 includes a hatch 43 on the left surface. The hatch 43 is openable and closable on the left side. When the hatch 43 is opened, the collection rack 31 of the paper feeding apparatus 16 appears. The collection rack 31 includes a moving mechanism 44 that moves from the inside of the finisher 4 to the left side. The user can set sheets to be reused in the collection rack 31 in a state in which the collection rack 31 is drawn out from the inside of the finisher 4 to the left side.

In the configuration shown in FIG. 3, the user sets the reuse sheets in a procedure explained below.

The user opens the hatch 43 and draws out the collection rack 31 from the inside of the finisher 4 to the left side. The user sets, in an erected state, sheets to be reused in the collection rack 31 drawn out to the left side. The user pushes the collection rack 31, in which the reuse sheets are set, into the finisher 4 and closes the hatch 43.

The collection rack 31 may be a collection rack that moves to the back or to the right side. For example, in the configuration of the digital multi function peripheral 1 shown in FIG. 1, the finisher 4 including the paper feeding apparatus 16 is connected to the left side of the printer 2. As shown in FIG. 1, in the configuration in which the finisher 4 is set on the left side of the printer 2, it is considered reasonable to move the collection rack 31 to the front side or the left side of the finisher 4 as shown in FIG. 2 or 3.

A first configuration example of the paper feeding apparatus 16 is explained in detail below.

FIG. 4 is a diagram of a paper feeding apparatus 16A according to the first configuration example.

In the first configuration example shown in FIG. 4, the paper feeding apparatus 16A includes the collection rack 31, a conveying roller pair (a pickup roller) 51, a conveying roller pair (a carry-out roller) 52, a blade 53 a, a blade 53 b, a conveyance guide plate 54 a, a conveyance guide plate 54 b, a conveying roller pair (a stop roller) 55, a conveying roller pair (a bottom roller) 56, a guide rib 57, and a tray 58.

The collection rack 31 has a mechanism (not shown) for pressing sheets stored in an erected state to the pickup roller 51 side. The pickup roller 51 captures one sheet moved to the endmost part of the collection rack 31. The pickup roller 51 conveys the captured sheet to the carry-out roller 52. In the configuration example shown in FIG. 4, the pickup roller 51 conveys the sheet in an arrow “a” direction.

The blades 53 a and 53 b function as a scraper that scrapes the surfaces of the sheet. The blades 53 a and 53 b function as a cleaning member that cleans the surfaces of the sheet and a rectifying member that rectifies the sheet to a flat state. In the configuration of this embodiment, the blades 53 a and 53 b hold a sheet being conveyed between the pickup roller 51 and the carry-out roller 52 to thereby respectively scrape both the surfaces of the sheet. As a result, the blades 53 a and 53 b scrape off foreign matters (dust) adhering to the surfaces of the sheet and rectify the state of the sheet.

When only one surface of the sheet has to be scraped, any one of the blades 53 a and 53 b may be set. As the cleaning member that cleans the surfaces of the sheet, members other than the blades may be used. For example, as the cleaning member, brushes that scrape off foreign matters adhering to the surfaces or sponges that scrape off foreign matters adhering to the surfaces can be applied. As the rectifying member that rectifies the sheet to a flat state, members other than the blades may be used. For example, as the rectifying member, rollers that apply stretching force to the sheet can be applied.

The foreign matters scraped off by the blades 53 a and 53 b drop with the own weight thereof. The tray 58 functions as a dust box that stores the foreign matters scraped off by the blades 53 a and 53 b. The tray 58 only has to store at least the foreign matters scraped off by the blades 53 a and 53 b.

The carry-out roller 52 conveys a part of the sheet that finishes passing through the blades 53 a and 53 b to the conveyance guide plates 54 a and 54 b side. The conveyance guide plats 54 a and 54 b guide the leading end of the sheet conveyed by the carry-out roller 52 to the stop roller 55. The sheet conveyed by the carry-out roller 52 passes between the conveyance guide plate 54 a and the conveyance guide plate 54 b. In the configuration example shown in FIG. 4, the carry-out roller 52 and the conveyance guide plates 54 a and 54 b convey the sheet in the arrow “a” direction. The stop roller 55 catches the leading end of the sheet guided by the conveyance guide plates 54 a and 54 b. When the stop roller 55 catches the leading end of the sheet conveyed by the carry-out roller 52, the carry-out roller 52 stops the conveyance of the sheet.

When the carry-out roller 52 stops the conveyance of the sheet, the bottom roller 56 catches the lower end of the sheet. When the bottom roller 56 catches the lower end of the sheet, the stop roller 55 releases the caught sheet. The bottom roller 56 may catch the lower end of the sheet released by the stop roller 55. When the stop roller 55 releases the sheet, the bottom roller 56 rotates to convey the sheet in a downward direction. In the configuration example shown in FIG. 4, the bottom roller 56 conveys the sheet in an arrow “b” direction.

The guide rib 57 guides a conveying direction of the sheet conveyed by the bottom roller 56. The guide rib 57 is formed by erecting plural tabular members. In the guide rib 57, the plural tabular members change a conveying direction of a falling sheet. For example, the guide rib 57 guides the sheet to a conveying mechanism in the finisher 4 for feeding the sheet to the printer 2.

The configuration of the blades 53 a and 53 b is explained in detail.

FIGS. 5 and 6 are diagrams of states of the blades 53 a and 53 b corresponding to conveying states of the sheet. In FIG. 5, the state of the blades 53 a and 53 b until the leading end of the sheet reaches the carry-out roller 52 is shown. In FIG. 6, the state of the blades 53 a and 53 b during conveyance of the sheet by the carry-out roller 52 is shown.

The blades 53 a and 53 b have a mechanism (not shown in the figure) for holding the sheet present between the pickup roller 51 and the carry-out roller 52 and releasing the sheet. The state shown in FIG. 5 is a release state in which the blades 53 a and 53 b release the sheet not to prevent the conveyance of the sheet. The state shown in FIG. 6 is a state in which the blades 53 a and 53 b hold the sheet present between the pickup roller 51 and the carry-out roller 52. The pickup roller 51 and the carry-out roller 52 convey the sheet even if the state in which the blades 53 a and 53 b hold the sheet as shown in FIG. 6 is maintained.

Specifically, until the leading end of the sheet conveyed by the pickup roller 51 reaches the carry-out roller 52, the blades 53 a and 53 b are in the release state shown in FIG. 5 not to prevent the conveyance of the sheet. When the leading end of the sheet conveyed by the pickup roller 51 reaches the carry-out roller 52, the carry-out roller 52 catches the sheet. When the carry-out roller 52 catches the sheet, as shown in FIG. 6, the blades 53 a and 53 b hold the sheet present between the pickup roller 51 and the carry-out roller 52. The pickup roller 51 and the carry-out roller 52 convey the sheet while the blades 53 a and 53 b keep holding the sheet.

Between the pickup roller 51 and the carry-out roller 52, the blades 53 a and 53 b hold the sheet conveyed thereto to thereby respectively strongly scrape both the surfaces of the sheet. For example, when the blade 53 a scrapes the front surface of the sheet, the blade 53 b scrapes the rear surface of the sheet. The blades 53 a and 53 b scrape both the surfaces of the sheet being conveyed to thereby scrape off foreign matters adhering to the surfaces of the sheet and rectify wrinkles, curls, or the like of the sheet.

In other words, the blades 53 a and 53 b have a function as blades that remove foreign matters and a function as levelers that rectify the state of the sheet to a flat state. Specifically, the blades 53 a and 53 b refresh the sheet (the reuse sheet) extracted from the collection rack 31. The sheet refreshed by the blades 53 a and 53 b can be expected to prevent deficiencies in the printer 2 and improve the quality of an image to be printed.

A second configuration example of the paper feeding apparatus 16 is explained below.

FIG. 7 is a diagram of a paper feeding apparatus 16B according to the second configuration example.

In the second configuration example shown in FIG. 7, the paper feeding apparatus 16B includes the collection rack 31, the conveying roller pair (the pickup roller) 51, the conveying roller pair (the carry-out roller) 52, the blade 53 a, the blade 53 b, a conveyance guide lattice 64 a, a conveyance guide lattice 64 b, the conveying roller pair (the stop roller) 55, the conveying roller pair (the bottom roller) 56, and the guide rib 57. In the paper feeding apparatus 16B shown in FIG. 7, the conveyance guide plates 54 a and 54 b in the paper feeding apparatus 16A shown in FIG. 4 are replaced with the conveyance guide lattices 64 a and 64 b.

In the paper feeding apparatus 16B shown in FIG. 7, the pickup roller 51 extracts one sheet from the collection rack 31. The sheet extracted by the pickup roller 51 is conveyed to the carry-out roller 52. Between the pickup roller 51 and the carry-out roller 52, the blades 53 a and 53 b scrape off foreign matters (dust) adhering to the surfaces of the sheet and rectify the state of the sheet.

The carry-out roller 52 conveys the sheet refreshed by the blades 53 a and 53 b to the conveyance guide lattices 64 a and 64 b. The conveyance guide lattices 64 a and 64 b guide the leading end of the sheet conveyed by the carry-out roller 52 to the stop roller 55. The sheet conveyed by the carry-out roller 52 passes between the conveyance guide lattice 64 a and the conveyance guide lattice 64 b. In the configuration example shown in FIG. 7, the carry-out roller 52 and the conveyance guide lattices 64 a and 64 b convey the sheet in the arrow “a” direction.

The conveyance guide lattices 64 a and 64 b are formed by lattice cells in which a sheet conveyed by the carry-out roller 52 and a sheet conveyed by the bottom roller 56 are not caught. For example, the conveyance guide lattices 64 a and 64 b may be formed by wires extending in the direction of conveyance by the carry-out roller 52 to prevent the sheet conveyed by the carry-out roller 52 from being caught. The lower ends of the conveyance guide lattices 64 a and 64 b may be provided above the lower end of the sheet conveyed by the carry-out roller 52 to prevent the falling sheet (the lower end of the sheet) from being caught. Any one of the conveyance guide lattices 64 a and 64 b may be replaced with the conveyance guide plate 54 a or 54 b.

When the stop roller 55 catches the leading end of the sheet guided by the conveyance guide lattices 64 a and 64 b, the carry-out roller 52 stops the conveyance of the sheet. When the carry-out roller 52 stops the conveyance of the sheet, the bottom roller 56 catches the lower end of the sheet supported by the conveyance guide lattices 64 a and 64 b and conveys the sheet in the downward direction. In the configuration example shown in FIG. 7, the bottom roller 56 conveys the sheet in the arrow “b” direction.

The guide rib 57 guides a conveying direction of the sheet conveyed by the bottom roller 56. The guide rib 57 changes the conveying direction of the falling sheet with the plural tabular members. Walls do not have to be formed on the sides of the guide rib 57 to smoothly remove dust.

A third configuration example of the paper feeding apparatus 16 is explained.

FIG. 8 is a diagram of a paper feeding apparatus 16C according to the third configuration example.

In the third configuration example shown in FIG. 8, the paper feeding apparatus 16C includes the collection rack 31, the conveying roller pair (the pickup roller) 51, the conveying roller pair (the carry-out roller) 52, the blade 53 a, the blade 53 b, the conveyance guide lattice 64 a, the conveyance guide plate 54 b, the conveying roller pair (the stop roller) 55, an assist roller 71, the conveying roller pair (the bottom roller) 56, and the guide rib 57. In the paper feeding apparatus 16C shown in FIG. 8, the conveyance guide plate 54 a in the paper feeding apparatus 16A shown in FIG. 4 is replaced with the conveyance guide lattice 64 a and the assist roller 71 is added.

In the paper feeding apparatus 16C shown in FIG. 8, the pickup roller 51 extracts one sheet from the collection rack 31. The sheet extracted by the pickup roller 51 is conveyed to the carry-out roller 52. Between the pickup roller 51 and the carry-out roller 52, the blades 53 a and 53 b scrape off foreign matters (dust) adhering to the surfaces of the sheet and rectify the state of the sheet.

The carry-out roller 52 conveys the sheet refreshed by the blades 53 a and 53 b to the conveyance guide lattice 64 a and the conveyance guide plate 54 b. The conveyance guide lattice 64 a and the conveyance guide plate 54 b guide the leading end of the sheet conveyed by the carry-out roller 52 to the stop roller 55. In the configuration example shown in FIG. 8, the sheet conveyed by the carry-out roller 52 moves in the arrow “a” direction between the conveyance guide lattice 64 a and the conveyance guide plate 54 b.

The conveyance guide lattice 64 a is formed by lattice cells in which a sheet conveyed by the carry-out roller 52 and a sheet conveyed by the bottom roller 56 are not caught. For example, the conveyance guide lattice 64 a may be formed by wires extending in the direction of conveyance by the carry-out roller 52 to prevent the sheet conveyed by the carry-out roller 52 from being caught. The lower end of the conveyance guide lattice 64 a may be provided above the lower end of the sheet conveyed by the carry-out roller 52 to prevent the falling sheet (the lower end of the sheet) from being caught.

When the stop roller 55 catches the leading end of the sheet guided by the conveyance guide lattice 64 a and the conveyance guide plate 54 b, the carry-out roller 52 stops the conveyance of the sheet. The assist roller 71 conveys the sheet supported by the conveyance guide lattice 64 a and the conveyance guide plate 54 b downward.

The assist roller 71 includes a driving mechanism 71 b that presses a conveying roller 71 a against the sheet from a space of a lattice cell of the conveyance guide lattice 64 a. While the carry-out roller 52 conveys the sheet (in the example shown in FIG. 8, while the carry-out roller 52 conveys the sheet in the arrow “a” direction), the driving mechanism 71 b of the assist roller 71 prevents the conveying roller 71 a from coming into contact with the sheet not to hinder the conveyance of the sheet. When the conveyance of the sheet by the carry-out roller 52 is stopped, the assist roller 71 presses the conveying roller 71 a against the sheet from the space of the lattice cell of the conveyance guide lattice 64 a. The conveying roller 71 a pressed against the sheet rotates to convey the sheet downward. The bottom roller 56 catches the sheet conveyed by the conveying roller 71 a and conveys the sheet downward. In the configuration example shown in FIG. 8, the conveying roller 71 a and the bottom roller 56 convey the sheet in the arrow “b” direction.

The assist roller 71 conveys the sheet by holding the sheet between the conveying roller 71 a and the conveyance guide plate 54 b. The assist roller 71 assists the downward conveyance of the sheet. A positional relation between the conveyance guide lattice 64 a and the conveyance guide plate 54 b may be reversed. In other words, the conveying direction of the sheet conveyed by the carry-out roller 52 may be guided by the conveyance guide plate 54 a and the conveyance guide lattice 64 b. When the paper feeding apparatus 16C includes the conveyance guide plate 54 a and the conveyance guide lattice 64 b, the assist roller 71 only has to press the conveying roller 71 a against the sheet from a space of a lattice cell of the conveyance guide lattice 64 b.

A fourth configuration example of the paper feeding apparatus 16 is explained below.

FIG. 9 is a diagram of a paper feeding apparatus 16D according to the fourth configuration example.

In the fourth configuration example shown in FIG. 9, the paper feeding apparatus 16D includes an inclined rack 81, the conveying roller pair (the pickup roller) 51, the conveying roller pair (the carry-out roller) 52, the blade 53 a, the blade 53 b, the conveyance guide lattice 64 a, the conveyance guide lattice 64 b, the conveying roller pair (the stop roller) 55, the conveying roller pair (the bottom roller) 56, the guide rib 57, and the tray 58. In the paper feeding apparatus 16D shown in FIG. 9, the collection rack 31 of the paper feeding apparatus 16B shown in FIG. 7 is replaced with the inclined rack 81. Detailed explanation of the operation and the like of the components other than the inclined rack 81 in the paper feeding apparatus 16D shown in FIG. 9 is omitted.

In the paper feeding apparatus 16D shown in FIG. 9, the incline rack 81 stores sheets in the same manner as the collection rack 31 of the paper feeding apparatus 16A, 16B, or 16C. The inclined rack 81 is a modification of the collection rack 31. The inclined rack 81 stores the sheets in an erected state. The bottom surface (a sheet supporting surface) of the inclined rack 81 is inclined at an angle α to be lower on a sheet extracting side. The user places sheets to be reused from a high side of the inclined rack 81 in the erected state. The sheets stored in the inclined rack 81 move to the lower bottom surface side because of the own weight of the sheets. In the inclined rack 81, the stored sheets tend to move to the sheet extracting side.

As explained above, the paper feeding apparatuses according to this embodiment have the configuration explained below.

The blades 53 a and 53 b scrape the surface of the sheet conveyed in the erected state. Foreign matters (paper powder, eraser waste, dust, staples, and the like) scraped off by the blades 53 a and 53 b drop with the own weight thereof. The tray 58 set below the blades 53 a and 53 b catches the foreign matters that drop with the own weight. When the blades 53 a and 53 b scrape off the foreign matters, the sheet is in the erected state. Therefore, it is less likely that the foreign matters scraped off by the blades 53 a and 53 b adhere to the surfaces of the sheet again.

The blades 53 a and 53 b scrape off foreign matters adhering to the surfaces of the sheet and apply the stretching force to the sheet. The blades 53 a and 53 b also play a role of levelers that apply the stretching force to the sheet to thereby rectify the sheet to flatten wrinkles, curls, or the like.

Sheets to be reused are vertically placed in the collection rack 31 or the inclined rack 81 in the paper feeding apparatus 16. When the sheets are vertically placed in the collection rack 31 or the inclined rack 81, it is easy to extract the sheets in order from the sheet set earliest (oldest sheet). In other words, first-in and first-out of the reuse sheets can be realized by vertically placing the sheets in the collection rack 31 or the inclined rack 81. In the configuration for the first-in and first-out of the reuse sheets, it is possible to prevent only specific sheets from being repeatedly used and equalize reuse frequencies of the sheets.

The paper feeding apparatus 16 feeds, after refreshing the sheets vertically placed in the collection rack 31 or the inclined rack 81 in the erected state, the sheets to the printer 2 in a laid state by changing a conveying direction. The printer 2 often includes a conveying mechanism that extracts a sheet in the laid state from the cassette and conveys the sheet. Since the paper feeding apparatus 16 feeds the sheet to the printer 2 in the laid state, the paper feeding apparatus 16 can be easily connected to the existing printer 2. Further, the paper feeding apparatus 16 feeds the refreshed sheet to the printer 2. Therefore, in the printer 2 connected to the paper feeding apparatus 16, it can be expected that deficiencies in a conveying system are reduced and a quality of an image printed on the sheet is improved.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiment shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. 

1. A paper feeding apparatus comprising: a rack that stores sheets in a vertically placed state; a first conveying roller that conveys a sheet extracted from the rack in a first direction in an erected state; a scraper that scrapes a surface of the sheet conveyed in the erected state by the first conveying roller; and a second conveying roller that conveys the sheet, the surface of which is scraped by the scraper, in a second direction different from the first direction.
 2. The apparatus according to claim 1, wherein the scraper is a blade brought into contact with the surface of the sheet conveyed by the first conveying roller.
 3. The apparatus according to claim 1, wherein the scraper is a pair of blades that hold the sheet conveyed by the first conveying roller.
 4. The apparatus according to claim 1, wherein the scraper is a cleaning member that cleans the surface of the sheet.
 5. The apparatus according to claim 1, wherein the scraper is a rectifying member that rectifies the sheet to a flat state.
 6. The apparatus according to claim 1, further comprising a tray set below a position where the scraper scrapes the surface of the sheet.
 7. The apparatus according to claim 1, further comprising a guide that guides the sheet, which is conveyed by the first conveying roller in the erected state and the surface of which is scraped by the scraper, to a stop position where the sheet conveyance in the first direction is stopped, wherein the second conveying roller conveys the sheet stopped in the stop position in the second direction.
 8. The apparatus according to claim 7, wherein the guide is a pair of plates.
 9. The apparatus according to claim 7, wherein the guide is a pair of lattices.
 10. The apparatus according to claim 7, wherein the guide is a combination of one plate and one lattice.
 11. The apparatus according to claim 7, further comprising an assist roller that conveys the sheet stopped in the stop position to the second conveying roller.
 12. The apparatus according to claim 1, wherein a bottom surface of the rack that supports the sheets in the vertically placed state is inclined to be lower on an extracting side of the stored sheets.
 13. An image forming apparatus comprising: a rack that stores sheets in a vertically placed state; a first conveying roller that conveys a sheet extracted from the rack in a first direction in an erected state; a scraper that scrapes the surface of the sheet conveyed in the erected state by the first conveying roller; a second conveying roller that conveys the sheet, the surface of which is scraped by the scraper, in a second direction different from the first direction; and a printer that forms an image on the sheet conveyed by the second conveying roller.
 14. The apparatus according to claim 13, further comprising a cassette that accumulates the sheet conveyed by the second conveying roller, wherein the printer forms an image on the sheet accumulated in the cassette.
 15. The apparatus according to claim 13, further comprising an erasing mechanism that erases an image on the sheet conveyed by the second conveying roller, wherein the printer forms an image on the sheet, the image on which is erased by the erasing mechanism.
 16. The apparatus according to claim 13, further comprising an erasing mechanism that erases an image on the sheet conveyed by the second conveying roller; and a cassette that accumulates the sheet, the image on which is erased by the erasing mechanism, wherein the printer forms an image on the sheet accumulated in the cassette.
 17. The apparatus according to claim 13, further comprising: a paper feeding unit that houses the rack, the first conveying roller, the scraper, and the second conveying roller and has a hatch for accessing the rack; and a printer unit that is connected to the paper feeding unit and houses the printer.
 18. The apparatus according to claim 17, further comprising a moving mechanism that moves the rack to an outside of the paper feeding unit in a state in which the hatch is opened.
 19. The apparatus according to claim 18, wherein the moving mechanism moves the rack to a front surface of the paper feeding unit in a state in which the hatch is opened.
 20. The apparatus according to claim 18, wherein the moving mechanism moves the rack to a surface on an opposite side of a connection surface with the printer unit in the paper feeding unit in the state in which the hatch is opened.
 21. An image forming method comprising: storing sheets in a rack in a vertically placed state; conveying a sheet extracted from the rack in a first direction in an erected state; scraping the surface of the sheet conveyed in the erected state; conveying the sheet, the surface of which is scraped, in a second direction different from the first direction; and forming an image on the sheet conveyed in the second direction. 